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In electrocatalysis, mechanistic analysis of reaction rate data often relies on the linearization of relatively simple rate equations; this is the basis for typical Tafel and reactant order dependence analyses. However, for more complex reaction phenomena, such as surface coverage effects or mixed control, these common linearization strategies will yield incomplete or uninterpretable results. Cohesive kinetic analysis, which is often used in thermocatalysis and involves quantitative model fitting for data collected over a wide range of reaction conditions, requires more data but also provides a more robust strategy for interrogating reaction mechanisms. In this work, we report a robotic system that improves the experimental workflow for collecting electrochemical rate data by automating sequential testing of up to 10 electrochemical cells, where each cell can have a different electrode, electrolyte, gas-phase reactant composition, and applied voltage. We used this system to investigate the mechanism of carbon dioxide electroreduction to carbon monoxide at several immobilized metal tetrapyrroles. Specifically, at cobalt phthalocyanine (CoPc), cobalt tetraphenylporphyrin (CoTPP), and iron phthalocyanine (FePc), we see signatures of complex reaction mechanisms, where observed bicarbonate and CO2 order dependences change with applied potential. We illustrate how phenomena such as electrolyte poisoning and potential-dependent degrees of rate control can explain the observed kinetic behaviors. Our mechanistic analysis suggests that CoPc and CoTPP share a similar reaction mechanism, akin to one previously proposed, whereas the mechanism for FePc likely involves a species later in the catalytic cycle as the most abundant reactive intermediate. Our study illustrates that complex reaction mechanisms that are not amenable to common Tafel and order dependence analyses may be quite prevalent across this class of immobilized metal tetrapyrrole electrocatalysts.
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Implantación de Prótesis de Válvulas Cardíacas , Insuficiencia de la Válvula Tricúspide , Humanos , Válvula Tricúspide/diagnóstico por imagen , Válvula Tricúspide/cirugía , Resultado del Tratamiento , Insuficiencia de la Válvula Tricúspide/diagnóstico por imagen , Insuficiencia de la Válvula Tricúspide/cirugía , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Cateterismo CardíacoRESUMEN
Direct electrochemical propylene epoxidation by means of water-oxidation intermediates presents a sustainable alternative to existing routes that involve hazardous chlorine or peroxide reagents. We report an oxidized palladium-platinum alloy catalyst (PdPtOx/C), which reaches a Faradaic efficiency of 66 ± 5% toward propylene epoxidation at 50 milliamperes per square centimeter at ambient temperature and pressure. Embedding platinum into the palladium oxide crystal structure stabilized oxidized platinum species, resulting in improved catalyst performance. The reaction kinetics suggest that epoxidation on PdPtOx/C proceeds through electrophilic attack by metal-bound peroxo intermediates. This work demonstrates an effective strategy for selective electrochemical oxygen-atom transfer from water, without mediators, for diverse oxygenation reactions.
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AIMS: MicroRNAs play a role in pathogenic mechanisms leading to heart failure. We measured a panel of 754 miRNAs in the myocardial tissue and in the serum of patients with heart failure with reduced ejection fraction due to dilatative idiopathic cardiomyopathy (DCM, N = 10) or ischaemic cardiomyopathy (N = 3), referred to left ventricular assist device implant. We aim to identify circulating miRNAs with high tissue co-expression, significantly associated to echocardiographic and haemodynamic measures. METHODS AND RESULTS: We have measured a panel of 754 miRNAs in the myocardial tissue [left ventricular (LV) apex] and in the serum obtained at the same time in a well selected study population of end-stage heart failure with reduced ejection fraction due to either DCM or ischaemic cardiomyopathy, referred to continuous flow left ventricular assist device implant. We observed moderate agreement for miR-30d, miR-126-3p, and miR-483-3p. MiR-30d was correlated to LV systolic as well as diastolic volumes (r = 0.78, P = 0.001 and r = 0.80, P = 0.005, respectively), while miR-126-3p was associated to mPAP and PCWP (r = -0.79, P = 0.007 and r = -0.80, P = 0.005, respectively). Finally, serum miR-483-3p had an association with right ventricular end diastolic diameter (r = -0.73, P = 0.02) and central venous pressure (CVP) (r - 0.68 p 0.03). CONCLUSIONS: In patients with DCM, few miRNAs are co-expressed in serum and tissue: They are related to LV remodelling (miR-30d), post-capillary pulmonary artery pressure (miR-126-3p), and right ventricular remodelling/filling pressures (miR-483-3p). Further studies are needed to confirm their role in diagnosis, prognosis or as therapeutic targets in heart failure with reduced ejection fraction.
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Cardiomiopatías , Insuficiencia Cardíaca , Hipertensión Pulmonar , MicroARNs , Isquemia Miocárdica , Disfunción Ventricular Izquierda , Humanos , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/genética , MicroARNs/genética , Remodelación VentricularRESUMEN
Artificial intelligence (AI) and machine learning (ML) is a promising field of cardiovascular medicine. Many AI tools have been shown to be efficacious with a high level of accuracy. Yet, their use in real life is not well established. In the era of health technology and data science, it is crucial to consider how these tools could improve healthcare delivery. This is particularly important in countries with limited resources, such as low- and middle-income countries (LMICs). LMICs have many barriers in the care continuum of cardiovascular diseases (CVD), and big portion of these barriers come from scarcity of resources, mainly financial and human power constraints. AI/ML could potentially improve healthcare delivery if appropriately applied in these countries. Expectedly, the current literature lacks original articles about AI/ML originating from these countries. It is important to start early with a stepwise approach to understand the obstacles these countries face in order to develop AI/ML-based solutions. This could be detrimental to many patients' lives, in addition to other expected advantages in other sectors, including the economy sector. In this report, we aim to review what is known about AI/ML in cardiovascular medicine, and to discuss how it could benefit LMICs.
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Background Emerging data suggest important prognostic value to left atrial (LA) characteristics, but the independent impact of LA function on outcome remains unsubstantiated. Thus, we aimed to define the incremental prognostic value of LA coupling index (LACI), coupling volumetric and mechanical LA characteristics and calculated as the ratio of left atrial volume index to tissue Doppler imaging a', in a large cohort of patients with isolated floppy mitral valve. Methods and Results All consecutive 4792 patients (61±16 years, 48% women) with isolated floppy mitral valve in sinus rhythm diagnosed at Mayo Clinic from 2003 to 2011, comprehensively characterized and with prospectively measured left atrial volume index and tissue Doppler imaging a' in routine practice, were enrolled, and their long-term survival analyzed. Overall, LACI was 5.8±3.7 and was <5 in 2422 versus ≥5 in 2370 patients. LACI was independently higher with older age, more mitral regurgitation (no 3.8±2.3, mild 5.1±3.0, moderate 6.5±3.8, and severe 7.8±4.3), and with diastolic (higher E/e') and systolic (higher end-systolic dimension) left ventricular dysfunction (all P≤0.0001). At diagnosis, higher LACI was associated with more severe presentation (more dyspnea, more severe functional tricuspid regurgitation, and elevated pulmonary artery pressure, all P≤0.0001) independently of age, sex, comorbidity index, ventricular function, and mitral regurgitation severity. During 7.0±3.0 years follow-up, 1146 patients underwent mitral valve surgery (94% repair, 6% replacement), and 880 died, 780 under medical management. In spline curve analysis, LACI ≥5 was identified as the threshold for excess mortality, with much reduced 10-year survival under medical management (60±2% versus 85±1% for LACI <5, P<0.0001), even after comprehensive adjustment (adjusted hazard ratio, 1.30 [95% CI, 1.10-1.53] for LACI ≥5; P=0.002). Association of LACI ≥5 with higher mortality persisted, stratifying by mitral regurgitation severity of LA enlargement grade (all P<0.001) and after propensity-score matching (P=0.02). Multiple statistical methods confirmed the significant incremental predictive power of LACI over left atrial volume index (all P<0.0001). Conclusions LA functional assessment by LACI in routine practice is achievable in a large number of patients with floppy mitral valve using conventional Doppler echocardiographic measurements. Higher LACI is associated with worse clinical presentation, but irrespective of baseline characteristics, LACI is strongly, independently, and incrementally determinant of outcome, demonstrating the crucial importance of LA functional response to mitral valve disease.
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Insuficiencia de la Válvula Mitral , Prolapso de la Válvula Mitral , Femenino , Atrios Cardíacos/diagnóstico por imagen , Humanos , Masculino , PronósticoRESUMEN
BACKGROUND: The dynamic consequences of mitral annular disjunction (MAD) on the mitral apparatus and the left ventricle remain unclear and are crucial in the context of mitral surgery. Thus, the aim of this study was to assess mitral valvular, annular, and ventricular dynamics in mitral valve prolapse (MVP) stratified by presence of MAD. METHODS: In 61 patients (mean age, 62 ± 11 years; 25% women) with MVP and severe mitral regurgitation undergoing mitral surgery between 2009 and 2016, valvular and annular dimensions and dynamics by two-dimensional transthoracic and three-dimensional transesophageal echocardiography and left ventricular dimensions and dynamics were analyzed stratified by presence of MAD before and after surgery. RESULTS: MAD (mean, 8 ± 3 mm) was diagnosed in 27 patients (44%; with a mean effective regurgitant orifice area of 0.55 ± 0.20 cm2 and similar to patients without MAD), more frequently in bileaflet prolapse (52% vs 18% in patients without MAD, P = .004), consistently involving P2 (P = .005). Patients with MAD displayed larger diastolic annular areas (mean, 1,646 ± 410 vs 1,380 ± 348 mm2), circumferences (mean, 150 ± 19 vs 137 ± 16 mm), and intercommissural diameters (mean, 48 ± 7 vs 43 ± 6 mm) compared with those without MAD (P ≤ .008 for all). Dynamically, mid- and late systolic excess intercommissural diameter, annular area, and circumference enlargement were associated with MAD (P ≤ .01 for all). MAD was also associated with dynamically annular slippage, larger prolapse volume and height (P ≤ .007), and larger leaflet area (mean, 2,053 ± 620 vs 1,692 ± 488 mm2, P = .01). Although patients with MAD compared with those without MAD showed similar ejection fractions (mean, 65 ± 5% vs 62 ± 8%, respectively, P = .10), systolic basal posterior thickness was increased in patients with MAD (mean, 19 ± 2 vs 15 ± 2 mm, P < .001), with higher systolic thickening of the basal posterior wall (mean, 74 ± 27% vs 50 ± 28%) and higher ratio of basal wall thickness to diameter (P ≤ .01 for both). However, after mitral repair, MAD disappeared, and LV diameter, wall thickness, and wall thickening showed no difference between patients with MAD and those without MAD (P ≥ .10 for all). CONCLUSIONS: MAD in patients with MVP involves a predominant phenotype of bileaflet MVP and causes profound annular dynamic alterations with considerable expansion and excess annular enlargement in systole, potentially affecting leaflet coaptation. MAD myocardial and annular slippage simulates vigorous left ventricular function without true benefit after surgical annular suture. Thus, although MAD does not hinder the feasibility and quality of valve repair, it requires careful suture of ring to ventricular myocardium, lest it persist postoperatively.
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Ecocardiografía Tridimensional , Insuficiencia de la Válvula Mitral , Prolapso de la Válvula Mitral , Ecocardiografía Transesofágica , Femenino , Humanos , Masculino , Válvula Mitral/diagnóstico por imagen , Válvula Mitral/cirugía , Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Insuficiencia de la Válvula Mitral/cirugía , Prolapso de la Válvula Mitral/diagnóstico por imagen , Prolapso de la Válvula Mitral/cirugíaRESUMEN
OBJECTIVES: This study aims to define excess-mortality linked to functional mitral regurgitation (FMR) quantified in routine-practice. BACKGROUND: Appraisal of FMR in heart failure with reduced ejection fraction (HFrEF) is challenging because risks of excess mortality remain uncertain and guidelines diverge. METHODS: Cases of HFrEF (ejection-fraction <50%) Stage B-C that were diagnosed between 2003 and 2011 and had routine-practice FMR quantitation (FMR cohort, n = 6,381) were analyzed for excess mortality thresholds/rates within the cohort and in comparison to the general population. These were also compared to those of a degenerative mitral regurgitation (DMR) simultaneous cohort (DMR cohort, n = 2,416). RESULTS: In the FMR cohort (age: 70 ± 11 years, ejection fraction: 36 ± 10%, effective regurgitant orifice area [EROA]: 0.09 ± 0.13 cm2), EROA distribution was skewed towards low-values (≥0.40 cm2 in only 8% vs 38% for the DMR cohort; P < 0.0001). One-year mortality was high (15.6%), increasing steeply from 13.3% without FMR to 28.5% with EROA ≥0.30 cm2 (adjusted odds ratio: 1.57 [95% CI: 1.19-2.97]; P = 0.001). In the long term, 3,538 FMR cohort patients died with excess mortality threshold â¼0.10 cm2 (vs â¼0.20 cm2 in the DMR cohort), with 0.10 cm2 EROA increments independently associated with considerable mortality increment (adjusted HR: 1.11 [95% CI: 1.08-1.15]; P < 0.0001) and with no detectable interaction. Compared to the general population, FMR excess mortality increased exponentially with higher EROA (risk ratio point estimates 2.8, 3.8, and 5.1 at EROA 0.20, 0.30, and 0.40 cm2, respectively), and was much steeper than that of the DMR cohort (P < 0.0001). In nested models, individualized EROA was the strongest FMR survival marker, and a new expanded FMR grading scale based on 0.10 cm2 EROA increments provided incremental power over current American Heart Association-American College of Cardiology/European Society of Cardiology guidelines (all P < 0.03). CONCLUSIONS: In HFrEF, FMR is skewed towards smaller EROA. Nevertheless, when measured in routine practice, EROA is the strongest independent FMR determinant of survival after diagnosis. Excess mortality increases exponentially above the threshold of 0.10 cm2, with a much steeper slope than in DMR, for any EROA increment. An expanded EROA-based stratification, superior to existing grading schemes in determining survival, should allow guideline harmonization.
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Insuficiencia Cardíaca , Insuficiencia de la Válvula Mitral , Disfunción Ventricular Izquierda , Anciano , Anciano de 80 o más Años , Insuficiencia Cardíaca/diagnóstico , Humanos , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Volumen Sistólico , Disfunción Ventricular Izquierda/complicacionesRESUMEN
OBJECTIVES: The aim of this study was to assess in patients with mitral valve prolapse (MVP) mitral annular disjunction (MAD) prevalence, phenotypic characteristics, and long-term outcomes (clinical arrhythmic events and excess mortality). BACKGROUND: Clinical knowledge regarding MAD of MVP remains limited and controversial, and its potential link with untoward outcomes is unsubstantiated. METHODS: A cohort of 595 (278 women, mean age 61 ± 16 years) consecutive patients with isolated MVP, with comprehensive clinical, rhythmic, Doppler echocardiographic, and consistent MAD assessment, were examined. MAD prevalence, associated MVP phenotypes, and outcomes (survival, clinical arrhythmic events) starting at diagnostic echocardiography were analyzed. To balance important baseline differences, propensity scoring matching was conducted among patients with and those without MAD. RESULTS: The presence of MAD was common (n = 186 [31%]) in patients with MVP, generally in younger patients, and was not random but was independently associated with severe myxomatous disease involving bileaflet MVP and marked leaflet redundancy (both P ≤ 0.0002). The presence of MAD was also independently associated with a larger left ventricle (P = 0.005). Age-matched cohort survival after MVP diagnosis was not worse with MAD (10-year survival 93% ± 2% for patients without MAD and 97% ± 1% for those with MAD; P = 0.40), even adjusted comprehensively for MVP characteristics (P = 0.80) and accounting for time-dependent mitral surgery (P = 0.60). During follow-up, 170 patients had clinical arrhythmic events (ventricular tachycardia, n = 159; arrhythmia ablation, n = 14; cardioverter-defibrillator implantation, n = 14; sudden cardiac death, n = 3). MAD was independently associated with higher risk for arrhythmic events (adjusted HR: 2.60; 95% CI: 1.87-3.62; P < 0.0001). The link between MAD and arrhythmic events persisted with time-dependent mitral surgery (adjusted HR: 2.54; 95% CI: 1.84-3.50; P < 0.0001), was strong under medical management (adjusted HR: 3.21; 95% CI: 2.03-5.06; P < 0.0001) but was weaker after mitral surgery (adjusted HR: 2.07; 95% CI: 1.24-3.43; P = 0.005). CONCLUSIONS: This large cohort with MVP comprehensively characterized shows that MAD is frequent at MVP diagnosis and is strongly linked to advanced myxomatous degeneration. The presence of MAD was independently associated with long-term excess incidence of clinical arrhythmic events. However, within the first 10 years post-diagnosis, MAD was not linked to excess mortality, and although reassurance should be provided from the survival point of view, careful monitoring for arrhythmias is in order for MAD.
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Insuficiencia de la Válvula Mitral , Prolapso de la Válvula Mitral , Anciano , Ecocardiografía , Femenino , Humanos , Persona de Mediana Edad , Válvula Mitral/diagnóstico por imagen , Válvula Mitral/cirugía , Prolapso de la Válvula Mitral/diagnóstico por imagen , Prolapso de la Válvula Mitral/etiología , Valor Predictivo de las PruebasRESUMEN
BACKGROUND: Left atrial assessment is complex, particularly in heart failure with reduced ejection fraction due to interactions with functional mitral regurgitation (FMR). Pilot data suggest that left atrial volumetric/mechanical coupling index (LACI) may be useful, but large outcome data are lacking. METHODS: We enrolled a comprehensively characterized cohort of patients in sinus rhythm with heart failure with reduced ejection fraction diagnosis at Mayo Clinic from 2007 to 2011. Routinely measured left atrial volume index and tissue-doppler-imaging a' allowed LACI calculation as (left atrial volume index)/(tissue-doppler-imaging a'). Survival was the outcome measured. RESULTS: The cohort's 4196 patients (69 [58-77] years, ejection fraction 40 [31-45]%) had mild FMR in 1505 and moderate-severe FMR in 1068. LACI was overall 5.06 (3.50-8.10) and increased with each FMR grade (3.86 [2.94-5.29] without FMR, 5.38 [3.80-8.02] with mild, 5.45 [1.49-8.07] with moderate/severe FMR; P<0.0001). At diagnosis, higher LACI was independently determined by more severe FMR and by higher left ventricular mass index, lower ejection fraction, higher E/e', and lower glomerular filtration rate (all P<0.0001). During follow-up 1588 (38%) patients died. In spline modeling, excess mortality appeared around LACI=6 and steeply increased thereafter (5-year survival 72±1% with LACI<6 and 49±2% with LACI ≥6, P<0.0001). Multivariable comprehensive adjustment showed LACI strong association with excess mortality (adjusted hazard ratio, 1.41 [1.23-1.61], P<0.0001 for LACI ≥6). Independent link to mortality persistent across FMR grades (adjusted hazard ratio, 1.45 [1.13-1.86], P=0.004 without FMR, 1.42 [1.16-1.77], P=0.0008 with mild FMR, and 1.38 [1.01-1.66], P=0.04 with moderate/severe FMR) without interaction (P=0.3). LACI independent impact on outcome was incremental to that of left atrial volume index, tissue-doppler-imaging a', or any other characteristic including the Meta-Analysis Global Group in Chronic-score (least significant P=0.02). CONCLUSIONS: In this large cohort, left atrial volumetric/mechanical coupling measured by LACI in routine practice integrates the influence of several morphological/hemodynamic determinants but displays progressive deterioration with increasing FMR severity in heart failure with reduced ejection fraction. About outcome, higher LACI is strongly, independently, and incrementally associated with excess mortality, irrespective of FMR grade and in all subsets. Hence, LACI is a novel and critical measure in heart failure with reduced ejection fraction, quantifiable in routine practice, which should be integrated in prognostication and decision-making.
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Ecocardiografía Doppler/métodos , Atrios Cardíacos/fisiopatología , Insuficiencia Cardíaca/fisiopatología , Volumen Sistólico/fisiología , Anciano , Anciano de 80 o más Años , Volumen Cardíaco , Femenino , Estudios de Seguimiento , Atrios Cardíacos/diagnóstico por imagen , Insuficiencia Cardíaca/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios RetrospectivosRESUMEN
Peri-operative echocardiography is widely used because it provides information that significantly influences clinical/surgical management and improves outcome in patients undergoing cardiac surgery. The role of intra-operative trans-esophageal echocardiography (TEE) in valvular heart disease cannot be emphasized enough. Increasing use of newer surgical techniques-valve repairs and minimal invasive cardiac surgery also warrants intra-operative TEE. It gives us better insight into the anatomy and physiology of the valvular lesion by digital imaging. This manuscript provides an illustrative case based overview of intra operative TEE (IOTEE) in heart valve surgery.
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BACKGROUND: Mitral valve prolapse (MVP) is often considered benign but recent suggestion of an arrhythmic MVP (AMVP) form remains incompletely defined and uncertain. OBJECTIVES: This study determined ventricular arrhythmia prevalence, severity, phenotypical context, and independent impact on outcome in patients with MVP. METHODS: A cohort of 595 (age 65 ± 16 years; 278 women) consecutive patients with MVP and comprehensive clinical, arrhythmia (24-h Holter monitoring) and Doppler-echocardiographic characterization, was identified. Long-term outcomes were analyzed. RESULTS: Ventricular arrhythmia was frequent (43% with at least ventricular ectopy ≥5%), most often moderate (ventricular tachycardia [VT]; 120 to 179 beats/min) in 27%, and rarely severe (VT ≥180 beats/min) in 9%. Presence of ventricular arrhythmia was associated with male sex, bileaflet prolapse, marked leaflet redundancy, mitral annulus disjunction (MAD), a larger left atrium and left ventricular end-systolic diameter, and T-wave inversion/ST-segment depression (all p ≤ 0.001). Severe ventricular arrhythmia was independently associated with presence of MAD, leaflet redundancy, and T-wave inversion/ST-segment depression (all p < 0.0001) but not with mitral regurgitation severity or ejection fraction. Overall mortality after arrhythmia diagnosis (8 years; 13 ± 2%) was strongly associated with arrhythmia severity (8 years; 10 ± 2% for no/trivial, 15 ± 3% for mild and/or moderate, and 24 ± 7% for severe arrhythmia; p = 0.02). Excess mortality was substantial for severe arrhythmia (univariate hazard ratio [HR]: 2.70; 95% confidence interval [CI]: 1.27 to 5.77; p = 0.01 vs. no/trivial arrhythmia), even after it was comprehensively adjusted, including for MVP characteristics (adjusted HR: 2.94; 95% CI: 1.36 to 6.36; p = 0.006) and by time-dependent analysis (adjusted HR: 3.25; 95% CI: 1.56 to 6.78; p = 0.002). Severe arrhythmia was also associated with higher rates of mortality, defibrillator implantation, VT ablation (adjusted HR: 4.68; 95% CI: 2.45 to 8.92; p < 0.0001), particularly under medical management (adjusted HR: 5.80; 95% CI: 2.75 to 12.23; p < 0.0001), and weakly post-mitral surgery (adjusted HR: 3.69; 95% CI: 0.93 to 14.74; p = 0.06). CONCLUSIONS: In this large cohort of patients with MVP, ventricular arrhythmia by Holter monitoring was frequent but rarely severe. AMVP was independently associated with phenotype dominated by MAD, marked leaflet redundancy, and repolarization abnormalities. Long-term severe arrhythmia was independently associated with notable excess mortality and reduced event-free survival, particularly under medical management. Therefore, AMVP is a clinical entity strongly associated with outcome and warrants careful risk assessment and well-designed clinical trials.
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Prolapso de la Válvula Mitral/complicaciones , Taquicardia Ventricular/complicaciones , Complejos Prematuros Ventriculares/complicaciones , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prolapso de la Válvula Mitral/diagnóstico , Prolapso de la Válvula Mitral/epidemiología , Fenotipo , Prevalencia , Índice de Severidad de la Enfermedad , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/epidemiología , Complejos Prematuros Ventriculares/diagnóstico , Complejos Prematuros Ventriculares/epidemiologíaRESUMEN
Understanding the function of nitric oxide, a lipophilic messenger in physiological processes across nervous, cardiovascular and immune systems, is currently impeded by the dearth of tools to deliver this gaseous molecule in situ to specific cells. To address this need, we have developed iron sulfide nanoclusters that catalyse nitric oxide generation from benign sodium nitrite in the presence of modest electric fields. Locally generated nitric oxide activates the nitric oxide-sensitive cation channel, transient receptor potential vanilloid family member 1 (TRPV1), and the latency of TRPV1-mediated Ca2+ responses can be controlled by varying the applied voltage. Integrating these electrocatalytic nanoclusters with multimaterial fibres allows nitric oxide-mediated neuronal interrogation in vivo. The in situ generation of nitric oxide in the ventral tegmental area with the electrocatalytic fibres evoked neuronal excitation in the targeted brain region and its excitatory projections. This nitric oxide generation platform may advance mechanistic studies of the role of nitric oxide in the nervous system and other organs.
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Técnicas Electroquímicas/métodos , Fenómenos Electrofisiológicos/fisiología , Neuronas , Óxido Nítrico , Animales , Encéfalo/citología , Encéfalo/fisiología , Calcio/metabolismo , Células HEK293 , Humanos , Masculino , Nanopartículas del Metal/química , Ratones , Ratones Endogámicos C57BL , Neuronas/metabolismo , Neuronas/fisiología , Óxido Nítrico/análisis , Óxido Nítrico/metabolismo , Canales Catiónicos TRPV/metabolismoRESUMEN
BACKGROUND: Etiology, mechanisms, and survival of mitral regurgitation (MR) plus hemodynamically-significant chronic aortic regurgitation (AR) are mostly unknown. OBJECTIVES: The purpose of this study was to investigate the prevalence, mechanisms, etiologies, and survival impact of coexistent ≥ moderate MR in AR patients. METHODS: Consecutive patients with ≥ moderate-severe AR were retrospectively identified between 2004 and 2019. RESULTS: Of 1,239 eligible patients (61 ± 18 years, 80% men), 1,072 (86%) had pure AR, and 167 (14%) had AR + MR (9% functional mitral regurgitation [FMR] [84% nonischemic] and 5% organic mitral regurgitation [OMR] [62% degenerative]). At baseline transthoracic echocardiogram, pure AR versus AR + OMR versus AR + FMR exhibited differences in age (59 ± 18, 62 ± 16, and 73 ± 14 years, respectively), female sex (18%, 27%, and 39%, respectively), symptoms (36%, 41%, and 64%, respectively), atrial fibrillation (5%, 17%, and 36%, respectively), left ventricular (LV) ejection fraction (59%, 58%, and 46%, respectively), LV end-systolic dimension and volume index, ≥ moderate tricuspid regurgitation (TR) (7%, 35%, and 53%, respectively), and right ventricular systolic pressure (32 ± 11, 45 ± 15, and 50 ± 14 mm Hg, respectively), all p < 0.0001. After a median follow-up of 5.2 years (interquartile range: 2.2 to 10.0 years) and adjusting for demographics, New York Heart Association functional class, aortic valve surgery, LV ejection fraction, LV end-systolic dimension and volume index, presence of FMR was independently associated with all-cause mortality (p ≤ 0.004). Compared with pure AR, AR + MR + TR exhibited the highest adjusted risk of death (2.4-fold; p < 0.0001). When compared with expected population survival, excess mortality risks of pure AR, AR + OMR, and AR + FMR were 1.25-fold, 1.76-fold, and 2.34-fold, respectively (all p ≤ 0.02). CONCLUSIONS: In hemodynamically significant AR, coexistent MR is not uncommon (approximately 14%) and mostly comprises FMR and less commonly OMR. As compared with pure AR, AR + MR + TR exhibit the largest mortality risk. Both AR + OMR and AR + FMR carry a survival penalty compared with the general population, but AR + FMR is associated with the largest excess mortality and represents an advanced stage within the AR clinical spectrum.
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Insuficiencia de la Válvula Aórtica/epidemiología , Insuficiencia de la Válvula Mitral/epidemiología , Volumen Sistólico/fisiología , Función Ventricular Izquierda/fisiología , Anciano , Insuficiencia de la Válvula Aórtica/diagnóstico , Insuficiencia de la Válvula Aórtica/fisiopatología , Enfermedad Crónica , Comorbilidad , Ecocardiografía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Insuficiencia de la Válvula Mitral/diagnóstico , Insuficiencia de la Válvula Mitral/fisiopatología , Morbilidad/tendencias , Estudios Retrospectivos , Taiwán/epidemiologíaRESUMEN
AIMS: To assess functional tricuspid regurgitation (FTR) determinants, consequences, and independent impact on outcome in degenerative mitral regurgitation (DMR). METHODS AND RESULTS: All patients diagnosed with isolated DMR 2003-2011, with structurally normal tricuspid leaflets, prospective FTR grading and systolic pulmonary artery pressure (sPAP) estimation by Doppler echocardiography at diagnosis were identified and long-term outcome analysed. The 5083 DMR eligible patients [63 ± 16 years, 47% female, ejection fraction (EF) 63 ± 7%, and sPAP 35 ± 13 mmHg] presented with FTR graded trivial in 45%, mild in 37%, moderate in 15%, and severe in 3%. While pulmonary hypertension (PHTN-sPAP ≥ 50 mmHg) was the most powerful FTR severity determinant, other strong FTR determinants were older age, female sex, lower left ventricle EF, DMR, and particularly atrial fibrillation (AFib) (all P ≤ 0.002). Functional tricuspid regurgitation moderate/severe was independently linked to more severe clinical presentation, more oedema, lower stroke volume, and impaired renal function (P ≤ 0.01). Survival (95% confidence interval) throughout follow-up [70% (69-72%) at 10 years] was strongly associated with FTR severity [82% (80-84%) for trivial, 69% (66-71%) for mild, 51% (47-57%) for moderate, and 26% (19-35%) for severe, P < 0.0001]. Excess mortality persisted after comprehensive adjustment [adjusted hazard ratio 1.40 (1.18-1.67) for moderate FTR and 2.10 (1.63-2.70) for severe FTR, P ≤ 0.01]. Excess mortality persisted adjusting for sPAP/right ventricular function (P < 0.0001), by matching [adjusted hazard ratios 2.08 (1.50-2.89), P < 0.0001] and vs. expected survival [risk ratio 1.79 (1.48-2.16), P < 0.0001]. Within 5-year of diagnosis valve surgery was performed in 73% (70-75%) and 15% (13-17%) of severe and moderate DMR and in only 26% (19-34%) and 6% (4-8%) of severe and moderate FTR. Valvular surgery improved outcome without alleviating completely higher mortality associated with FTR (P < 0.0001). CONCLUSION: In this large DMR cohort, FTR was frequent and causally, not only linked to PHTN but also to other factors, particularly AFib. Higher FTR severity is associated at diagnosis with more severe clinical presentation. Long term, FTR is independently of all confounders, associated with considerably worse mortality. Functional tricuspid regurgitation moderate and even severe is profoundly undertreated. Thus careful assessment, consideration for tricuspid surgery, and testing of new transcatheter therapy is warranted.
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Insuficiencia de la Válvula Mitral , Insuficiencia de la Válvula Tricúspide , Anciano , Femenino , Humanos , Masculino , Válvula Mitral/diagnóstico por imagen , Estudios Prospectivos , Estudios Retrospectivos , Volumen Sistólico , Insuficiencia de la Válvula Tricúspide/diagnóstico por imagenRESUMEN
BACKGROUND: This study aims to investigate the association of wall shear stress (WSS) and aortic strain with circulating biomarkers including matrix metalloproteinases (MMP), tissue inhibitors of metalloproteinase (TIMP), and exosomal level of microRNA (miRNA) in ascending aortic aneurysms of patients with bicuspid or tricuspid aortic valve. METHODS: A total of 76 variables from 125 patients with ascending aortic aneurysms were collected from (1) blood plasma to measure plasma levels of miRNAs and protein activity; (2) computational flow analysis to estimate peak systolic WSS and time-average WSS (TAWSS); and (3) imaging analysis of computed tomography angiography to determine aortic wall strain. Principal component analysis followed by logistic regression allowed the development of a predictive model of aortic surgery by combining biomechanical descriptors and biomarkers. RESULTS: The protein activity of MMP-1, TIMP-1, and MMP-2 was positively correlated to the systolic WSS and TAWSS observed in the proximal ascending aorta (eg, R = 0.52, P < .001, for MMP-1 with TAWSS) where local maxima of WSS were found. For bicuspid patients, aortic wall strain was associated with miR-26a (R = 0.55, P = .041) and miR-320a (R = 0.69, P < .001), which shows a significant difference between bicuspid and tricuspid patients. Receiver-operating characteristics curves revealed that the combination of WSS, MMP-1, TIMP-1, and MMP-12 is predictive of aortic surgery (area under the curve 0.898). CONCLUSIONS: Increased flow-based and structural descriptors of ascending aortic aneurysms are associated with high levels of circulating biomarkers, implicating adverse vascular remodeling in the dilated aorta by mechanotransduction. A combination of shear stress and circulating biomarkers has the potential to improve the decision-making process for ascending aortic aneurysms to a highly individualized level.
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Aorta/fisiopatología , Aneurisma de la Aorta Torácica/fisiopatología , Válvula Aórtica/anomalías , Estrés Mecánico , Adulto , Anciano , Aneurisma de la Aorta Torácica/sangre , Aneurisma de la Aorta Torácica/cirugía , Válvula Aórtica/fisiopatología , Enfermedad de la Válvula Aórtica Bicúspide/cirugía , Biomarcadores , Femenino , Humanos , Modelos Logísticos , Masculino , Metaloproteinasa 1 de la Matriz/sangre , Metaloproteinasa 12 de la Matriz/sangre , Mecanotransducción Celular , MicroARNs/sangre , Persona de Mediana Edad , Inhibidor Tisular de Metaloproteinasa-1/sangre , Remodelación VascularAsunto(s)
Insuficiencia de la Válvula Aórtica/diagnóstico por imagen , Válvula Aórtica/diagnóstico por imagen , Enfermedad de la Válvula Aórtica Bicúspide/diagnóstico por imagen , Ecocardiografía , Adulto , Válvula Aórtica/fisiopatología , Insuficiencia de la Válvula Aórtica/etiología , Insuficiencia de la Válvula Aórtica/fisiopatología , Enfermedad de la Válvula Aórtica Bicúspide/complicaciones , Enfermedad de la Válvula Aórtica Bicúspide/fisiopatología , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: Transcatheter edge-to-edge repair with MitraClip is only approved for treatment of mitral regurgitation but is increasingly used to treat concomitant tricuspid regurgitation (TR) due to its common coexistence and association with poor outcomes. This study aimed to describe the learning curve associated with the challenge of off-label treatment of concomitant TR. METHODS: This is a retrospective review of initial and consecutive patients who underwent combined edge-to-edge repair of mitral and tricuspid valves (TVs) at our institution from August 2017 to October 2019. RESULTS: Repair of both valves with MitraClip was performed in 22 patients (median age 81.5 years, 32% female). Mean procedure time was 176 ± 47 min; mean fluoroscopy time was 65 ± 24 min. Procedure duration in the first tertile was significantly longer (223 ± 13 min) than in the third tertile (143 ± 23 min, p = .0003). Median number of total clips placed per case was 3; in 15 patients (68%), the anterior and septal leaflets of the TV were clipped. The average changes in mean right atrial (RA) and left atrial (LA) pressures were -1.7 ± 2.5 mmHg (p = .0080) and -3.2 ± 4.6 mmHg (p = .0045), respectively. The average changes in RA and LA V-wave heights were -3.3 ± 4.0 mmHg (p = .0009) and -8.1 ± 9.9 mmHg (p = .038), respectively. There was a significant trend toward decreasing residual TR over the course of the series (p = .046). At 30 days, survival was 100% and mean NYHA class decreased from 2.8 to 1.8 (p < .0001). CONCLUSIONS: Combined edge-to-edge tricuspid and mitral valve repair is safe and feasible. With experience, procedure duration and residual TR decreased.